Apparatus for cutting rectangular openings in doors and the like



Jan. 14, 1958 w. G. BIRKEL' ETAL 2,819,743

APPARATUS FOR CUTTING RECTANGULAR OPENINGS IN DOORS AND THE LIKE Filed Nov.-2, 1956 1 4 Sheets-Sheet 1 INVENT'ORS WALTER G. BIRKEL ROBERT E. SCHRAM ATTORNEY Jan. 14, 1958 w. G. BIRKEL ETAL 2,819,743

APPARATus FOR CUTTING RECTANGULAR OPENINGS IN DOORS AND THE LIKE Filed Nov. 2, 1956 4 Sheets-Sheet 2 4/ T 4a '2? 42 4 T l 45 i- W 9 a A I a a3 z -34 52 Z f 55 71/1 III/Ill 55" g g I 3 5 54- 54 E A 36 Z/ r g 53 Q g as I E A? \z 37 s A INVENTORS WALTER e. BIRKEL ROBERT E. SCHRAM T ATTORNEY Jan. 14, 1958 Filed Nov. 2, 1956 w. G. BIRKEL ETAL 2,819,743 APPARATUS FOR CUTTING RECTANGULAR OPENINGS IN DOORS AND THE LIKE 4 Sheets-Sheet 3 INVENTORS WALTER 6.8IRKEL A ROBERT E. SCHRAM ATTORNEY Jan. 14, 1958 w G r 2,819,743

APPARATUS FOR CU TANGULAR OPENINGS IN IKE Filed Nov. 2, 1956 BIRKEL TTING REC DOORS AND THE L 4 Sheets-Sheet 4 ATTORNEY APPARATUS FOR CUTTING RECTANGULAR OPENINGS IN DOORS AND THE LIKE Walter G. Birkel, Lynbrook, N. Y., and Robert E. Schram, Paramus, N. J., assignors to Hardware Products Corporation, Neenah, Wis.,. a corporation of Wisconsin Application November 2, 1956, Serial No. 620,061

14- Claims. (Cl. 143-48) This invention relates to apparatus for cutting rectangular openings in doors and the like;- and resides more particularly in the combination of: a cutter-head; a workholding table, traversable longitudinally and laterally relative to the cutter-head; a single circular-saw blade, lying in a plane substantially perpendicular to the work,,a nd mounted on a stub-axle extending to one side only ofrthe blade, said stub-axle being journaled in the cutter-head; means, supported on the cutter-head, and surrounding the stub-axle and the end of the cutter-head, for cutting'a path through the work to enable the stub-axle and the end of the cutter-head to pass therethrough, so that the blade can cut clear to the corners of the opening; means for swiveling the cutter-head about an axis perpendicular to the Work, to change the orientation of the blade in successive increments of 90; and means for advancing the cutter-head into the work, perpendicularly thereto, and for withdrawing the cutter-head therefrom; all motions being considered as relative.

Still more particularly the invention resides insuch apparatus, wherein the recited motions are absolute.

Invention also inheres in thecutter-head per se, and in certain details of various elements of thecutter-head and its associated mechanisms.

It is the principal object of the invention to provide novel, useful, and simple apparatus for cutting rectangular openings in doors and the like:

It is a further object of the invention to provide such an apparatus which will perform the entire operation, insuring absolute rectangularity, without splintering, andwithout the need of clean-up, especially not at the corners of the opening.

It is a further object of the invention to dispense with the use of reciprocating cutters, and to eliminate the need of aligning successive cutters-for cutting anyone kerf.

It is a further object of the invention to provide such an apparatus in which the entire cutting of the opening, per se, is done with a single circular-saw blade, even at the corners of the opening.

It is a further object of the invention to accomplish the reorientation of the plane of the circular-saw blade, by power, without the employment of an additional powerdrive for this purpose.

Inasmuch as the cut-out pieces have a definitersalvage value, it is a further object of the invention, to provide an apparatus which will remove these. pieces as intact as possible.

These and other'objects and advantages of the invention will appear in the description to follow.

It is to be understood that, although the invention is designed, primarily, for cutting openings indoors itmay be used for other similar purposes, such, as for cutting openings in panels or other wall-sections.

.In the description, reference is made to the. accompanying drawings which forrna part hereof, andinwhichthere. is shown, by way of illustration but not of limitatiomone specific form in which the invention may be: embodied.

mechanism per se, or many 2,819,743 Patented Jan. 14, 1958 In the drawings:

Fig. I isa parallel perspective view of the present invention, largely conventionalized. It illustrates the relative positioning of the cutter-head assembly, the door, the work-holding means, and. the means for traversing the latter both longitudinally and laterally.

Fig. 2 is a longitudinal elevation, partly in section, viewed as though out along the line 22 of Fig.1. It illustrates a typical wheel mounting,"whereby 'the" workholding-table rolls laterally on the tracks of theintermediate table; It is to a more open scale than Fig. 1.

Fig. 3 is a transverse elevation, partly in section, viewed as though cutalong the line 3-3 of Fig. 1. It illustrates, in addition to another view of the subject-matter of Fig. 2, a typical wheel mounting, whereby- 'the'intermediate table rolls longitudinally on the tracks-of the stationary base. It is to a more open scale than, Fig. 1.

Fig. 4 is a vertical section of the cutter-head assembly, showing the cutter-head in its low' position, with the circu-' lar saw completely out of the door.

Fig. 5 is the same view, showingthe cutter-head'in'its intermediate position,'with the circular saw through'the door.

Fig. 6 is a part of the same view, showing the cutterhead in its high position, with both the circular saw, and the path-cutting means through the door.

' Fig. 7 is an'open-scale elevation of the circular saw, path-cutting means, and part of the cutter-head, viewed-as seen from the left in Fig. 8.

Fig. 8 is a view of the same, to thesa'me scale as'Fig117, partly in elevation and partly in section,-viewed as though cut along the line 8-8 of Fig. 4. I

Fig. 9 is a horizontal section, to the same 'scale' as Fig.7, viewed as though cut along the line9- 9 of Fig-:4. It illustrates the means for locking the cutter-head to i'tsbase, against swiveling about its vertical axis.

Fig.-10 (sheet 1) is an enlargedelevation of'a special clamp to hold the cut-out portion of the doorin place,- during cutting.

Throughout the description, the same reference number is applied'to the same member or similar members.

Referring now to the drawings, more particularly"to Figs. 1, 2, and 3, it will be seen that Fig. l is largely conventionalized, inasmuch as no invention .is' claimed. to inhere in the work-supporting means or thetraversing other of the details,'such as 'thevariouselamping means.

The work-holding table comprises two transverse chan nels 11,- and two longitudinal channels 12'. The work13, more specifically a door, may be clamped to the Work holding table by any appropriate means, such as four G- clamps 14. Depending from thetransver'se channels'll of' the work-holding table are a series of wheels 15' (see; Figs. 2 and 3), which run on transverse tracks 16, to be hereinafter mentioned.

Below the workholding table '11-12,there is an intermediate-table,comprising two transverse channels 17, and two longitudinal channels 18. Transverse channels 17' supporttracks 16,-already mentioned. Depending from transverse channels 17 are a series of wheeis'19 '(see'Fig', 3'), which run on longitudinal tracks" 20, to be hereinafter', mentioned.

Below the intermediate table 17-18, there is a stationary base, comprising two longitudinal I-beams 21, "resti'ng.

on piers 22. These I-beams carry longitudinal rack 23,

which is engaged by pinion24, actuable"by"motor.. '25.

able by motor 28 on the work-holding table. Actuation of this pinion causes the work-holding; table (and the door carried thereby) to traverse laterally.

Brakes to lock the two tables in various traversed positions, duplication of the traversing mechanisms for greater stability, and other details not claimed per se, will readily suggest themselves.

Part of door 13 is shown cut-away, to expose the cutterhead assembly, which will now be described.

Turning to Figs. 4, 5, and 6, it will be seen that 29 is the cutter-head which carries the cutting machinery to be hereinafter described. Cutter-head 29 is supported by elevator 30. The two are interlocked in some appropriate manner (such as shown at the top edge of the latter), so as to keep the head from pullingotf from the top of the elevator, and to maintain the two axially aligned, and yet permit the head to swivel about a vertical axis with respect to the elevator.

Elevator 30 is a hollow cylinder, supported in turn by, and slidable vertically with respect to, the upper portion 31 of a base 32, which is stationary with respect to stationary base 20 of the traversing mechanism.

Pins 33, projecting from upper portion 31 of base 32, and slidable in vertical slots 340i elevator 30, prevent the elevator from swiveling, while permitting vertical move ment thereof.

Swivelable about a constricted portion 35 of base ,32,

asi'av- Rigid with this shaft 48, there are seven sprocket wheels 49. All ten sprocket wheels are similar to sprocket wheel 49 shown in Fig. 8.

Rigid with shaft 48 is a bevel gear 50, meshing with bevel pinion 51, rigid with the upper end of vertical shaft 52, in the swivel axis of cutter-head 29.

Hollow vertical shaft 53 is shown surrounding vertical shaft 52. Splines 54, carried by the lower end of shaft 52 slide in splineways 55, thus enabling these two shafts to telescope and yet still rotate in unison.

Shaft 53 is driven by a power source, not shown, preferably at constant speed; and thereby, through shaft 52,

I pinion 51, and gear 50, drives shaft 48, and the seven sprocket wheels 49 thereon. These seven sprocket wheels cuttingly drive the seven chain-saw chains 47, which constitute the path-cutting means. Three of these chains drive the three sprockets 43, which in turn cuttingly drive circular saw40, through its stub axle.

there is an elevating screw 36, which operatively meshes with elevating nut 37, rigid with the lower end of elevator 30. Integral with screw 36, there is a bevel gear 38,,meshing with bevel pinion 39, which is driven by a power source, not shown. Preferably this pinionhas two slow elevating speeds, and one fast lowering speed, for reasons which will hereinafter appear.

Fig. 4 shows the relative positions of the above-described elements of the elevating mechanism, when cutterhead 29 is in its low position, with all cutting parts clear of the work 13.

Fig. 5 shows the relative positions, when cutter-head 29 is in its intermediate position, with circular saw 40 projecting through the work 13.

Fig. 6 shows the relative positions, when cutter-head 29 is in its high position, with not only circular saw 40 projecting through the door, but also the path-cutting means (to be hereinafter described) projecting through the work 13.

The cutting-means will now be described. See Figs. 4, 7, and 8. This comprises circular saw 40, and a pathcutting'means preferably made-up of chain-saw elements. Except as specified in the claims, the details and the numbers of similar elementsare merely illustrative. For example, the chain-saw chains might be in accordance with U. S. Patent No. 2,508,784 to Cox. As shown in Fig. 7, the cutting elements of each chain occur between the cutting elements of adjacent chains; and alternate, overlapflilg first the chain to the right and then the chain to the Stub axle 41, rigid with circular saw 40, is journaled in the upper end of extension 42 of cutter-head 29. Rigid with this axle, there are three sprocket wheels 43. At each side of these three sprocket wheels are two grooves 45. These grooves may extend to the lower end of extension 42, as shown in Fig 8. Three similar grooves may extend from space 46 (Fig. 4) to the lower endof extension 42. These seven grooves are for guiding the seven chain-saw chains 47; see Figs. 7 and 8. In Fig. 8, for the sake of simplicity, only the nearer chain 47 is shown; those chains lying between it and circular saw 40 are not shown. In view of the fact, which will appear hereinafter, that chains 47 are used only to cut vertical holes the three similar grooves and the portion of grooves extending below sprocket wheels 43, might be omitted, though their retention is advisable.

. Drive shaft 48 is shown journaled in cutter-head 29.

clockwise when viewed from above.

The journaling of this axle 41 in extension 42 is rendered possible by having only three of the seven chainsaw chains 47 serve as drive-chains for circular saw 49, and hence only three sprocket wheels 43 mounted on axle 41.

The chain-saw chains 47 could be joined together into a single cutting band without losing their identity, but this would havethe disadvantage of not providing as smooth a drive for circular saw 40 as do the separate chains.

Next as to the means for orienting circular saw 40. Reverting to Fig. 4, it will be seen that, in order to impart to circular saw 40 the direction of rotation indicated by the arrow in Fig. 8, pinion 51 will have to rotate counter- Assume that the resistance (due to friction and inertia) of the various parts carried by cutter-head 29 and actuated by pinion 51, to motion with respect to the cutter-head, is greater than the resistance of the cutter-head and parts carried thereby, considered as a unit, to swiveling with respect to the base. Then, unless the cutter-head is locked against such swiveling, the rotation of pinion 51 will cause the cutter-head to swivel; whereas if it is so locked the rotation of pinion 51 will cause the cutting mechanism to operate. The above-mentioned torque-differential could be accentuated by the interposition of anti-friction bearings at the juncture of cutter-head 29 and elevator 30.

In view of this, the following locking mechanism is provided. Compare Figs. 9 and 4. ;.'Ihe periphery of cutter-head 29 is provided, adjacent its lower extremity, with four horizontal holes 56, 90 apart. Plunger 57,- reciprocable in horizontal hole 58 in elevator 30, is spring-actuated to pass into any one of holes 56 which may be opposite it. The spring (not shown) and a solenoid (not shown) for opposing the spring, are contained in box 59. When it is desired to change the orientation of circular saw 40, the solenoid is momentarily actuated, thus withdrawing plunger 57. Whereupon pinion 51 swivels cutter-head 29 counterclockwise (as viewed from above) until the next hole 56 comes opposite the plunger, which thereupon locks the cutter-head against further swiveling.

Inasmuch as elevator 30 is keyed against swiveling with respect to base 32, then (sofar as the swivel-locking mechanism justdescribed is concerned) the elevator may be functionally considered as a part of the base.

Revertingto Fig. l, the cycle of operations will now be described.

With the cutter-head 29 in low position beneath-the door 13, and the circular saw 40 oriented in a longitudinal plane, the door is traversed untilthe cutting mechanism is below corner A of the hole to be cut. The circular saw and the cutting-chains arerunning.

The cutter-head'is then elevated to its high position, the saw. cutting the extremeA end-of kerf AB, and the chains cutting the path .60. The fact that, as has-been seen earlier herein, the chains completely surround the stub-axle of the saw and the upper end of extension 42 of the cutter-head, permits the axis of the saw to pass through this path 60, thus permitting the edge of the saw to cut a clean vertical end of the kerf, clear to corner A.

The cutter-head is then retracted to its intermediate position, with only the saw blade projecting through the door, and the door is traversed longitudinally (toward the lower right hand corner of the figure) until the kerf AB is cut to B. Whereupon the cutter-head is raised to its high position, squaring the B end of kerf AB.

The cutter-head is then retracted to its low position, with all cutting means completely out of and below the door. The cutter-head is then swiveled 90 counterclockwise, thus putting it in position to cut the kerf BC as it did the kerf AB.

As shown in Fig. 1 the saw 40, at intermediate height, is cutting the kerf BC, from B toward C, as the door is being traversed laterally toward the upper right hand corner of the figure.

The process is repeated for kerfs CD and DA. Appropriate means for holding the cut-out portion rigid with respect to the door during" cutting, and for removing it at the end thereof, should be provided. Such means might take the form of, say, three clamps such as illustrated in Figure 10, wherein a bolt 61 is integral with a fixed bottom-cross-piece 62. A movable top-cross-piece 63 is slidable up-and-down on bolt 61, and (if desired) may be keyed thereto. A wing-nut 64 completes the assembly. Bottom-piece 62 should preferably have its ends beveled to edges 65, and should be less in length than the horizontal diagonals of holes 60.

After the two holes 60 at each of corners B, C, and D, have been cut, one of these clamps should be inserted in one of the holes of each corner, and then be oriented so that its cross-pieces 62 and 63 underlie and overlie both the door and the piece which is being cut out, and then nut 64 should be tightened.

After the cutting is completed, the clamps can be loosened and used to assist in removing the cut-out piece.

As already stated earlier herein, the elevating means has two slow speeds for raising the cutter-head, and one fast speed for lowering it. This saves time in lowering, when no resistance has to be met; and enables the use of a slow speed while the circular saw is cutting upward through the door, and a still slower speed while the chains are cutting upward through the door.

Appropriate controls, automatic or otherwise, may be employed for all the functions of the apparatus, and the sequence of operations.

In the claims it will be assumed that all motions are relative, unless expressly stated to be absolute.

It will be readily evident from the foregoing description that the present invention affords a novel and useful mechanism for cutting rectangular openings in doors and the like, which invention attains the objects and advantages set forth herein.

Now that one embodiment of the invention has been shown and described, and several variations therefrom have been suggested, it is to be understood that the invention is not limited to the specific form or arrangement of parts herein shown and described.

What is claimed is:

1. In an apparatus for cutting rectangular openings in doors and the like, the combination of: a cutter-head; work-holding means, for rigidly supporting the work; means for traversing the work-holding means longitudinally and laterally relative to the cutter-head; a single circular-saw blade; a stub axle rigid with the blade, and extending to one side only of the blade, for drivably supporting the blade; means, adjacent the end of the cutterhead, for journaling the stub axle on the cutter-head, so that the blade lies in a plane substantially perpendicular to the work; means, supported on the cutter-head, and surrounding the stub axle and the end of the cutter-head, for cutting a path through the work, to enable the stub axle and the end of the cutter-head to pass therethrough; means for cuttingly rotating the blade and for cuttingly operating the path-cutting means; means forswiveling the cutter-head about an axis substantially perpendicular to the work, in successive increments of and means for advancing the cutter-head to and into the work in a direction substantially perpendicular thereto, and for withdrawing the cutter-head therefrom.

2. Apparatus according to claim 1, wherein the workholding means holds the work substantially horizontally; and wherein all the recited motions are absolute; and wherein the cutter-head approaches the work from below.

3. A cutter-head assembly for use in an apparatus for cutting rectangular openingsin doors and the like, which apparatus includes work-holding means for rigidly sup porting the work, and for traversing the work longitudinally and laterally relative to the cutter-head assembly, said cutter-head assembly comprising: a cutter-head; a stub axle rigid with the blade, and extending to one side only of the blade, for drivably supporting the blade; means; adjacent the end of the cutter-head, for journaling the stub axle on the cutter-head, so that the blade lies in a plane substantially perpendicular to the work; means, supported on the cutter-head, and surrounding the stub axle and the end of the cutter-head, for cutting a path through the work, to enable the stub axle and the end of the cutter-head to pass therethrough; means for cuttingly rotating the blade and for cuttingly operating the path-cutting means; and means for advancing the cutter-head to and into the work in a direction substantially perpendicular thereto, and for withdrawing the cutter-head therefrom.

4. A cutter-head assembly according to claim 3, wherein there is means for changing the orientation of the saw blade, with respect to the work, in successive increments of 90, by swiveling the cutter-head about an axis substantially perpendicular to the work.

5. A cutter-head assembly according to claim 3, wherein there are: a base, on which the cutter-head is mounted for swiveling about an axis substantially perpendicular to the work; a shaft, journaled in the base, and axially aligned with the axis of said swiveling; means on the base for imparting rotation to said shaft; means drivingly connecting said shaft to the path-cutting means and the circular-saw blade, to cuttingly actuate them whenever the cutter-head is held against swiveling; and means for locking, at will, the cutter-head to the base, against swiveling, the torque necessary to overcome the resistance of the various parts carried by the cutter-head and actuated by the axial shaft, to motion with respect to the cutter-head, being greater than the torque necessary to overcome the resistance of the cutter-head and parts carried thereby, to swiveling motion with respect to the base.

6. A cutter-head assembly according to claim 3, wherein the path-cutting means comprises a plurality of chainsaw cutting-chains, trained around the stub axle and the end of the cutter-head.

7. A cutter-head assembly according to claim 6, wherein the means for rotating the blade and operating the path-cutting means includes: a drive shaft remote from the stub axle and parallel thereto, and at least one chainengaging sprocket wheel on and constrained to rotate with said shaft, and at least one chain-engaging sprocket wheel on and constrained to rotate with the stub axle; whereby at least one of the chains serves to rotate the blade.

8. A cutter-head assembly according to claim 7, wherein there is guide means for at least one of the cuttingchains around that portion of the end of the cutter-head where the stub axle is journaled.

9. A cutter-head assembly according to claim 3, wherein the path-cutting means comprises a plurality of chainsaw cutting-chains, trained around the stub axle and the end'of the cutterhead; and wherein there areza base, on which the cutter-head;,is mounted for swiveling about an axis substantially 'perpendicular with the work; a shaft, journaledin the-base, and axially aligned with the axis of said swiveling; means onthebase for imparting rotation to saidshaft; means drivingly connecting said shaft to the cutting-chains and the circular-saw blade, to cuttingly actuate them'whenever the cutter-head is held againsfswivelitig; and means for looking, at will, the cutter-head to the base in positions 90 apart, against swivelingywhereby the axialshaft serves 'to swivel the eutter-head in' increments 'of"90, whenever the locking meansis not-locked.

10. A cutter-headassembly'aceording to claim '9, wherein the locking means comprises: alplunger slidably carried by'the base, and movable towards: and away from the cutter-head substantially radially with respect thereto; a succession of holes forreceiving the end of the plunger, spaced 90Tcapart around periphery of the cutter-lt'ead; means for 'biasing' the. plunger. towards the cutter-head; and means' for momentarily. withdrawing the plunger from the hole occupiedby it.

11. A cutter-head assemblyaccording to claim '10, wherein the biasing means comprises a' spring, and the withdrawing means comprises a' solenoid. v

12. A cutter-head assembly comprising: a'base; a cutter-head-mounted on the base, for swiveling with respect to the base;'cutting'means, mounted on the head, for cutting motion with respect thereto; a;shaft', journaled in the baseyand axially aligned with theaxis of said swiveling, for imparting such cutting motion to the cutting means, whenever the cutter-head is held against swiveling; means on the base 'for imparting rotation to the shaft; and means for locking, at'will, the cutter-head to the base, againstswivelingythe torque necessary to overcome the resistance'of the various parts, carried by the cutter-head and actuated by the axial shaft, to motionwith respect to the cutter-head, being greater than the torquenecessary to overcome the resistance of-the cutterhead andpar'ts' carried thereby, to swiveling motion with respect'tothe base.

13. Acutter-headassembly comprising: a cutter-head; a single-circular-saw blade;- a stub axle rigid with the blade; and extending to'one'side only of the blade, for drivably supportingthe blade; means, adjacent the end of the cutter-head,-for-journaling the stub axle-on the cutter-head; a plurality of chain-saw cutting-chains, trained around the stub-axle-and the end of the cutterhead, for cutting a-path through the work, to enable the stubEaxle-..a'ncl the end of the'cxitter-head to pass therethrough; and means for cuttingly rotating the circularsaw'blade and for cuttinglyoperating the cutting-chains.

14. A cutter headassernbly"according to claim 13, wherein the means for rotating the blade and operating the cutting-chains includes a drive shaft remote from the stub axle and parallel thereto, and at least one chainengaging-sprocket-on and constrained to rotate with said shaft, andat leastone chain-engaging sprocket on and constrained to rotate with the stub axle; whereby at least one of the-chains serves to rotate the blade.

""References Cited in the" file of this patent UNITED STATES PATENTS UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent Noo 2,819,743 January 14, 1958 Walter G: Birkel 'et ale It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as cor-= reoted' belowu In the grarrt lines 3 and 13, and in the heading to the printed specifi cation, lines 5 and 6, name of assignee, for "Hardware Products Corporation" each ooomenoe, read me Hardwood Products Corporation Signed and sealed this 22nd day of April 1958,,

Attest:

KARL o AXLINB ROBERT c. WATSON Attesting Officer Comnissioner of Patents 

